EP1215118B1 - Test bench for thrust reverser - Google Patents

Description

Object of the invention

The field of application concerned by this invention is that of aviation and aeronautics.

The present invention relates to a device for testing the proper functioning of a thrust reverser present on a motor type turbojet, said test being carried out on the ground on a bench indoor or outdoor test.

State of the art

Until the early 1940s, the mode of classic propulsion of civilian or military aircraft was the piston engine that operated one or more propellers and allowed to move the planes through the rotation of propellers (s) rejecting the air towards the rear of the planes. Then have appeared the first turbojet engines "Single-flow turbojets" that use another mode propulsion: propulsion by reaction.

A single-flow turbojet is constituted a faired enclosure that sucks and compresses the air of outside. A combustion reaction takes place in a combustion chamber between the heated air and the combustible. The flue gases go through a turbine at which they give up some of their energy, which will be used for the compressor stage. Then the flue gases are ejected backwards where they relax at great velocity in a nozzle, exerting on the walls of this thrust a nozzle which ensures the propulsion of the aircraft by reaction.

Some civil or military aircraft use today as a means of propulsion a turbofan, also called "turbofan engine". The planes thus equipped are less noisy and consume less energy than aircraft equipped with jet engines simple flow. In this type of reactor, part of the air sucked is not heated and suffers only a slight compression before being directly rejected into the nozzle.

In order for them to brake, planes civilian jet aircraft are equipped with a particular device mounted on the turbojet engine and called "inverter of thrust. The thrust reverser is a device presenting in the form of a deflector that allows for deflect in the opposite direction to the push, that is to say towards the front of the reactor all or part of the gases and so to obtain, as its name indicates, an inversion of thrust.

There are two main types of inverters thrust: shells inverters and thrust reversers grilles or shutters. Shell inverters are constituted by half-shells that are placed directly in the flow of gases, and in particular air, and deflect the flow laterally. Inverters to grilles or shutters are mainly used to deflect the cold flow of turbofans. of the examples of thrust reversers are given in the EP-B1-0 043 764, EP-B1-0 067 747 and FR-A-2 559 838 and EP-B1-0 310 497.

It is imperative to be able to test the good operation of these thrust reversers in order to check their characteristics and behavior of the both mechanical and aerodynamic point of view. Indeed, these thrust reversers are a critical piece of the airplane, their malfunction in flight having already been several times causing crashes. The problem is that the tests currently carried out on the functioning of thrust reversers themselves present risks, to the extent that they must be performed either in flight, on the ground in outdoor test benches. Benches Ground Indoor Test Templates Typically Used to Test the other parts of the plane can not indeed be in this particular case, since the circulation of the flow of gas imposed by the test bench and that of the inverter of in the opposite direction, which would lead to a deterioration of both the bench and the inverter to be tested, as well as reinjection, by the engine to the test, burnt gas, which can cause a stall of this engine with risk of damage to it.

However, at present, no solution that would solve this thrust reverser test problem has yet been proposed.
The publication of Charles M. Mehalic and Roy A. Lottig (NASA), entitled "Full-Scale Thrust Reversing Testing in an Altitude Facility" , AIAA Paper, No. 87-1788, 1987, pages 1-13, XP001004710 discloses a system inverter gas collection system for testing a thrust reverser under different flight conditions. The inverter collection system is capable of capturing the secondary exhaust gases from the inverter and transporting them to the primary exhaust gas collection system. It is specified that this inverter collection system comprises two rectangular section conduits, a support structure for these conduits and a conical section adapter capable of adapting to the primary exhaust manifold.

Goals of the invention

The present invention aims to solve this problem of ground testing thrust reversers in a indoor test bench or outdoor test bench.

The present invention aims more precisely at provide a simple solution to use and moderate cost.

The present invention also aims to provide a solution that is reliable and offers the maximum of security.

The present invention further aims to provide a solution that can also be used in the case a test without thrust reverser.

Summary of the invention

The present invention relates to a bench test to test the operation of an inverter thrust of an engine, preferably a turbojet equipped with said thrust reverser, said engine being capable of to suck and evacuate the air in a certain sense according to a primary flow and said thrust reverser being capable to circulate the gases from combustion between the air and at least one fuel according to a secondary flow, directed in a direction essentially opposed to said flow primary, said bench being characterized in that it is provided with means for collecting and recovering said gases from the thrust reverser, said means being able to redirect the gases coming out of this inverter from thrust in the direction of said primary flow.

According to the invention, said collection means and gas recovery, which are able to redirect the gases coming out of the thrust reverser in the direction said primary stream, comprise at least one deflector and two half-shells, preferably metal, vis-à-vis and open at least on one outer face, each half-shell being divided into separate compartments by essentially parallel walls so as to allow a laminar flow of the gas stream.

Preferably, said collection means and gas recovery systems are also provided with attachment to the thrust reverser and / or the engine.

Another object of the present invention is the use of this test bench as a test bench interior to ground test the operation of a thrust reverser.

Finally, the present invention relates to also to the use of test bench as a test bench outside to ground test the operation of a thrust reverser.

Brief description of the figures

FIG. 1 represents a view showing the positioning of the flow collector at the output of the thrust reverser of a turbojet in the bench Inner test according to the invention.

Description of a preferred embodiment of the invention

An example of thrust reverser to test in an indoor test bench according to the present invention is illustrated in Figure 1. The turbojet engine being able to suck and evacuate the air in a certain direction according to a primary flow schematized by the arrow A, this thrust reverser to test 1 is able to do circulate the burned gases, resulting from combustion between the air and at least one fuel, according to a directed secondary flow in a sense essentially opposite to said primary flow and schematized by the arrow B. At the exit of the inverter of push are arranged means 2 of collection and recovery of the air from the thrust reverser. These means 2 comprise two half-shells 3, for example metal, arranged opposite and open on a face. These half-shells 3 are provided with at least one deflector 4. The air coming from the thrust reverser is thus recovered inside the half-shells 3 and redirected in the direction of said primary stream, as shown arrows C. Each half-shell 3 is divided into compartments separated from each other by walls essentially parallel in order to allow a laminar flow of the gas stream. In addition, baffles 4 positioned inside the half-shells 3 allow a rational distribution of the fluid vein at the level of collection means 2.

Claims (4)

1. Test bed intended to test the functioning of the thrust reverser (1) of an engine, preferably a turbojet, provided with said thrust reverser (1), said engine being able to draw in and expel the air in a specific direction according to a primary flow (A), and said thrust reverser (1) being able to circulate the gases derived from the combustion between the air and at least one fuel according to a secondary flow (B), directed in a direction substantially opposite to that of said primary flow (A), said bed being provided with means (2) for collecting and recovering said gases (B) derived from the thrust reverser (1), said means being able to redirect the gases (B) exiting this thrust reverser (1) in the direction of said primary flow (A), characterised in that said collection and recovery means (2) for the gases comprise two half-shells (3), preferably made of metal, facing each other, open at least on one external face and each divided into compartments separated by walls (4) that are substantially parallel so as to allow a laminar flow of the gas flow.
2. Test bed according to Claim 1, characterised in that said collection and recovery means (2) for the gases are also provided with fixing means to the thrust reverser (1) and/or to the engine.
3. Use of the test bed according to Claim 1 or 2 as an internal test bed for ground-testing the functioning of a thrust reverser.
4. Use of the device according to Claim 1 or 2 as an external test bed for ground-testing the functioning of a thrust reverser.

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